TRG3 Solder Bridge Factory Assembly Bug
During the calibration of the CS-80 I stumbled upon an interesting problem which must have been there from the start and none of the former owner(s) seemed to have noticed, including myself.
When I was calibrating the aftertouch VCO levels I was desperately fighting with one trimpot (VR2) on the TRG3 board. The terminal I measured kept showing 15.6V, disregarding any turns except when I got near the left starting point, where it jumped to 8.6V. The adjustment goal was actually 6.0V.
After some analyzation, a friend gave me the hint to check the back side of the board for suspicious anomalies, and alas, there were two soldering points bridged that are not supposed to be connected at all.
Judging the way the soldering points look, that bridge must have been there from the start (QA fail, tsk tsk).
The result of that bridge is, increasing the aftertouch pressure on this voice will have a shorter VCO aftertouch buildup curve than the other voices, reaching max volume way earlier than the other voices.
After fixing those pads, turning the trimpot finally worked as expected, the readings looked good and I was able to adjust it properly. Fortunately, this false connection didn't do any damage on the belonging IG00151.
That was surely my daily wtf for that day.
When I was calibrating the aftertouch VCO levels I was desperately fighting with one trimpot (VR2) on the TRG3 board. The terminal I measured kept showing 15.6V, disregarding any turns except when I got near the left starting point, where it jumped to 8.6V. The adjustment goal was actually 6.0V.
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| Solder bridge bug |
Judging the way the soldering points look, that bridge must have been there from the start (QA fail, tsk tsk).
The result of that bridge is, increasing the aftertouch pressure on this voice will have a shorter VCO aftertouch buildup curve than the other voices, reaching max volume way earlier than the other voices.
After fixing those pads, turning the trimpot finally worked as expected, the readings looked good and I was able to adjust it properly. Fortunately, this false connection didn't do any damage on the belonging IG00151.
That was surely my daily wtf for that day.
TRG3 Solder Bridge Factory Assembly Bug
Reviewed by MFox
on
6:27 PM
Rating:
Reviewed by MFox
on
6:27 PM
Rating:
